There has been a continual need for sintering nonoxide ceramics efficiently, particularly those that are suitable for high-hardness and high-temperature applications, such as are required for drill and tool bits and for ceramic armor. Boron carbide is an excellent lightweight material for ceramic armor and high-wear applications. However, the material does not sinter well, requiring temperatures over 2200.degree. C. for densification with or without hot-pressing. Microwave sintering has been attempted with boron carbide with requirements still of temperatures about 2100.degree. C. for densification. This development has shown that densification can result below 2000.degree. C. with a new material that should be useful in all the typical areas of boron carbide usage.